Safety tools



April 4, 1951 w. R. MEIER SAFETY TooLs Filed sept. 27, 195e IN VEN TOR.//a/ef/Q Me/er Bk 'to reach its kindling point.

United States Y l, A

2,918,353 sAFErYTooLs,

Walter R. Mee'r,` LincolnNeb'rr. if" (143 S. Rose Lane, Columbus?,Nebr.)

Filed sept. 21, 1956, ser. No. 612,563 g z ciaima.- (0.11.1537) t `fromsoft material.` 1i Tools ofsoft materials, the m'ost popular `one Vofwhich' has` been Vberyllium copper, are claimedv by their producersto'bespark-proof, although they are notcompletely spark-proof,wherebyfthere'is a'possibility'of.danger.y in their use. r 1

.'Presentlyavailable safety tools havefurther disadvantages in that theyare` frequently made over-sized in an attemptrto overcome their weaknesswhereby they will not workproperlyin confined places. They have afuryther disadvantage in that their. life is Vvery short as they areeasily damaged beyond usability, and'they are of no value where severestrain must be exerted to do a job. f ,For these reasonsv steel toolsare being used in place of, the recommended safety tools in `violationof safety codes. i ,J It is an' object of this' invention to providetools that are completely spark-proof to eliminate. all possibility 'ofsparking and explosion, and which are also as hard as a le and as toughas conventional steel tools.

A further object', of this invention isftoprprovide tools which are notAsubject tok corrosion, showing little or no reaction t acids. Y v i Iam aware thatrthere arev many tools, already on the vmarket,havingcoresv surroundedY with coating material,

however none have coatings suitable for my safety tools. Such tools havecoatings Ywhich are neither sufficiently hard nor suliicieritly'thick toserve the purposes of the tools of ,myv invention.'4 ,n

j'ItisQa further 'objective'to provide tools so constructed l -o provideIassurance againstthe possibility of the ycoatirig-being'jworn awayinnormal use whereby the tools would be. no longerY safqwherepthere isdanger of explosion from spark. t, e

Patented Apr. 4, 1961 sparks in my opinion, and also is the cause of thevisible orange light of a toolrspark. The orange light does not comefrom electricity atrall, nor even from magnetic permeability, but doescome fromY the super-heat of oxida-A tion.

Because of this theory I haveV proceeded to develop tools having a toughcorre surrounded with arspark-proof, corrosion-proof case, the casebeing formed of a nonsteel material which is non-corrosive whereby itsfragments will not unite with the oxygen in the air even though theyhavereachedvthekindiing temperature of steel whereby the super-heat'fromoxidation lvis neverzgenf erated and the tool is thereby more safe. t tAccordingly it is possible by this concept to use acasing material whichis actually of a greater hardness than steel whereby a greater amount ofVforce is required tol knock a fragment of it loose from vthe tool thanin the caseV of a fragment of steel, nevertheless the fragment of mycasing can reach a temperature higher than the kindling temperature of'a kfragment of steel and yet will noty kindle or oxidizebecause' of itsvnon-corrosive characteristics, thereby having a lesser tendency tooxidize. Safety tools have heretofore been' mad'eof expensive materialssuch as beryllium copper kand these expensive materials have been usedthroughouteach such tool. It is an object of my invention to provide atool made with a relatively inexpensive core and coated with asparkproof, corrosive-proof case, in this way substantially reducing thecost of safety tools. i

' A further object of my invention is in the provision of a tool havingan inexpensive core, having a spark# l proof, corrosion-proof casing atthe ends or other Yworkas being electrical sparks. At the same time theyhave .thought of these sparks as being caused by the steel conlwhen heldto a grinding wheel.

It has beena common test of a tool, in determining whether it isasafetool to use in explosion danger areas,

toapply a magnet to the tool. If the magnet is attracted to the tool itis believed to contain too high a percentage of steel to be a safe tool.Y i It is my theory that toolsparks are caused'by a fragf'ment of thetool being torn awayv from the remainder of the tool with sufficientforce for causing the fragment It is my further; concept that thefragment then oxidizes and the oxidationvprocess causes it. to reachfatemperature far in excessief its ing surfaces of -the tool and having avery inexpensive' spark-proof` plastic` coating on handle areas, andother non-working areas of the tool in order to furtherfconserveexpensive spark-proof metal coating material to make the'tools stillmore inexpensive. Other and further objects and advantages of thepresent invention will be apparent from the following detaileddescription', drawings and claims, the scope of thein vention not beinglimited to the drawings lthemselves as the drawings are only for thepurpose of illustrating a way in which the principles of this inventioncan be applied.

Other embodiments of the invention utilizing the same or equivalentprinciples may be used and structural changes may be made as desired bythoseskill'edyyin the art without departing frornjthelpresentiriventionand'the purviewrof the ,appendedrclaims f I In thedrawings:

VFigure 1 islatop Yplan viw of a hand wrench Ywithi'oneY modification'of Va sparkproof coating of my invention atp-jV plied thereto;

Figure 2 is a plan view of one lend of a hand'ivreiich i showing adifferent modification of the spark proof coatl ing of my invention asapplied thereto;

` the lines-5 of Figure 2.l

kindlingtemperature. This super-heat, as I prefer to call '#,isthe realcause of explosion danger from safety tool Referring to the drawing, 1nFigure la wrench 8 is shown having a core 1i) having a'suitablepreferably metallic sparkproof coating material 12 in accordance with'myinvention and'covering the workingsurfaces of the wrench. lSuch acoating caribe vapproximately 1A.; inch if desired. Y

A suitableplastic coating 14 encases the handle por-* tion .of thewrench 16v and can be of greater thicknessV` `than the coating v12, ifdesired, without excess'cost, for

' example approximately 17525.

In Figure 2 a wrench 20 is shown having a core 21 having a workingsurface coating 22 and a handle or non-working surface coating 24, bothof a same suitable sparkproof material such as ay metal. The coating 22is of approximately a 1454 inch thicknessV or more if desired althoughthe handle coatingv 24 can be of much lesser thickness when hard metalis used, as shown,

such as between ve and ten thousandths or more since' the wear on anonworking surface is muchV less.

VThe coatings 12, 14, 22 and 24 are otherwise made according to any ofthe instructions hereinafter set forth in detail.

Process of manufacture I prefer to coat my cores by the metallizingprocess which is the spraying of the coating material on the core.Thereafter the tool can be subjected to heat until the coating issintered, causing the coating to form a continuous, imperviousprotective casing. The sintering step is necessary `because themetallizing spraying causes the coating to be relatively porous whereasthe sintering causes it to be a continuous coating in which theindividual particles strongly adhere.

I use either boron or silicon, or both, as an ingredient of the formulaof the casing material because either boron or silicon function as aflux in the sintering process.

The boron and silicon serve two purposes because after they have servedtheir purpose as a flux they serve the further purpose of beinghardening agents.

I prefer totuse boron as the ux and hardening agent because then thecoating can be sintered in the atmosphere whereas with most of the otherhardening agents, sintering must be carried out in ovens with reducedoxygen. It is necessary to have a liux to prevent steel from oxidizinguntil such time as the coating has reached a temperature suicient forsintering. Y

However, when an oven is used of the type having gas in it which doesnot have substantial oxygen content, then it is possible to use coating.materials which do not contain flux.

In such ways of manufacture and when ux is unnecessary, 'it is possibleto use other hardening agents such as aluminum oxide, ferrous zinc,tungsten, molybdenum, tantalum or the various carbide alloys.

Another and preferred process of applying the coating is to coat thetool with the casing material by applying the `coating material likepaint by mixing the powdered coating material with a suitable vehicle,such as thermoplastic acrylic resin, then sintering the coating as abovedescribed, the resin burning away in the sintering process, to leave acontinuous coating of metal.

A further way of applying the coating is in the application of powderedcoating material to the core by pressing the powdered material aroundthe core in a die. Following this the tool is removed from the die andis then heated until the coating is sintered.

A further method of manufacture would be in applying the casing materialto the core in a mold and then sintering the casing material while thetool is still in the same mold and before removing it.

Butryrate and vinyl plastisol symbolize the plastic group that might beused `on nonvvorking surfaces. Other plastics might be used. AForinstance acrylic or epoxy resins mixed with powdered Ametals would makesuitable coatings or handlesfornonworking surfaces.

From the foregoing description, it is thought to be obvious that safetytools constructed in accordance with my invention are particularly welladapted for use, by

i reason of the convenience andfaclity with which they may be assembled'and operated, and it will also be obvious that my invention issusceptible of some change and modification without departing from theprinciples and spirit thereof, and for this reason I do not wish to beunderstood as limiting myself to the precise arrangement and formationof the several parts herein shown in carrying out my invention inpractice, except as claimed.

I claim:

l. In a spark-proof 4hand tool of the character described, an innerframe of steel defining the basic shape and location of thework-engaging surfaces of the tool, and a non-sparking coating over theentire surface of said tool, said coating consisting essentially of vanickelchromium-boron alloyintegrally united with said internal Iframe,therthickness of said coating over said -woi'kengaging surface beingapproximately its of an inch.

V2. In a spark-proof hand tool of the character described, an innerframe of steel defining the basic shape and location of thework-engaging surfaces of the tool anda non-sparking coating over theentire surface of said tool, said coating Aon the work-engaging surfacesofthe tool consisting vessentially of a nickel-chromiurn-boronalloyintegrally. united with said internal surfaces and said coating onthe non-work-engaging surfaces consisting essentially offa syntheticresin integrally united with said surfaces,` the thickness of saidcoating over said Workengaging surface being approximateiy 3%:4 of aninch.

i References Cited in the le of this patent UNITED STATES PATENTS 61,133Allen Jan. 15, 1867 u1,864,590 Field June 28, 1932 1,894,820 Gregg Jan.17, 1933 2,261,228 Cockrum Nov. 4, 1941 2,645,145 Parson July 14, 19532,656,751 Johnson et al. Oct. 27, 1953 Y 2,680,984 Ingwer June 15, 19542,726,165 Isler Dec. 6, 1955 OTHER REFERENCES VModern Plastic, vol. 17,June 1940, page S2.

2. IN A SPARK-PROOF HAND TOOL OF THE CHARACTER DESCRIBED, AN INNER FRAMEOF STEEL DEFINING THE BASIC SHAPE AND LOCATION OF THE WORK-ENGAGINGSURFACES OF THE TOOL AND A NON-SPARKING COATING OVER THE ENTIRE SURFACEOF SAID TOOL, SAID COATING ON THE WORK-ENGAGING SURFACES OF THE TOOLCONSISTING ESSENTIALLY OF A NICKEL-CHROMIUM-BORON ALLOY INTEGRALLYUNITED WITH SAID INTERNAL SURFACES AND SAID COATING ON THENON-WORK-ENGAGING SURFACES CONSISTING ESSENTIALLY OF A SNYTHETIC RESININTEGRALLY UNITED WITH SAID SURFACES, THE THICKNESS OF SAID COATING OVERSAID WORKENGAGING SURFACE BEING APPROXIMATELY 1/64 OF AN INCH.